There really doesn't seem to be anything online for it does there? What did you find on worthpoint, the same board?
You say disassembly, does this computer have a case? Looks like a PC/AT clone or full size AT board that's an early-ish 386, probably wasn't cheap.

It looks like it's fully discrete and going by the chip dates was made some time after week 40 of 1989. From your pictures it doesn't look like it's suffered battery damage so what I'd do is first check for shorts between 5v > ground and 12v > ground, to make sure that no tantalum capacitors have gone short.
Then back up the BIOS chips and see if those can be recombined / read to see what the BIOS string is, perhaps that could help.

From there, plug the motherboard+RAM card into a current limited / bench power supply with a PicoPSU and test whether it powers up / runs with a POST card hooked up. The PicoPSU and current limited power supply are what I use the first time a board is run to see that nothing is shorting and the PicoPSU (with an ATX > AT adapter cable) has really good short & under/over-voltage protections. Like this: Re: What retro activity did you get up to today?

It looks like your 386's memory board has 4MB of parity RAM fitted and assuming it'll all work without a battery fitted, it should really 'just work'. If it doesn't, re-seat / clean any jumpers you can find, maybe re-seat chips / clean legs on chips where you can see corrosion. Further troubleshooting can be much more complicated but it looks like that computer's been stored well.

Thanks for advice, your dates sound correct.

It looks like it is 88/89 going by chip dates. Iguess It would of been high end at the timegiven the presense of the other cards I found in the system.

A, DTC7287 MFM/RLL card and a Expert TopVGA 2100 /w WD90C90-JK/Paradise Systems PVGA1A-JK .

The CPU is a 386 dx25 /w double sigma (ΣΣ)

Here are some better pics.

I wouldnt call a 1989 386 system with MFM and no simm sockets high end exactly.

rasz_pl wrote on 2023-08-19, 02:27:

I wouldnt call a 1989 386 system with MFM and no simm sockets high end exactly.

Agree ! More like the non-chipset 286 made to run a 386 board. Not even SIPP memory which my 1989 286 has.....😁
Added: oops 286 actually has a very early VSLI 100 series chipset so might be 1990.... my bad ;p

Wow. No unified chipset in sight. Probably one of the last motherboards before chipsets took over entirely. It’s beautiful.

Do save it!

Hehe, see if a sxl2 works in it!! :p

Hmmm Ok for some reason makes me think of an early DTK board ??

Horun wrote on 2023-08-19, 02:55:

Hmmm Ok for some reason makes me think of an early DTK board ??

It's made in the USA though and so is the memory board.

It seems odd to me too. How many companies were manufacturing 386 Boards with 32-bit external memory card slots and all discrete logic in the United States in the late 80s. Its uncommon and knowing that there were 8-9 others like this in a shed that the guys wife trashed when they were moving to their new house I know there is at least that many less of them.

I think i found it. However this is not the exact board.

https://arvutimuuseum.ee/th99/m/E-H/31318.htm

This is that worthpoint.
https://www.worthpoint.com/worthopedia/vintag … king-1828452332

Do you have the original hard disk drive?
I was wondering if the controller might be ESDI.
The only reference I found was an eBay listing that claims the controller Is MFM/

FYI, FWIW, DTC-5280 ... seems like a good fit for the HDD/FDC controller card

Anonymous Coward wrote on 2023-08-19, 11:13:

Do you have the original hard disk drive?
I was wondering if the controller might be ESDI.
The only reference I found was an eBay listing that claims the controller Is MFM/

I can do better, I found the manual. Too bad it doesn't do IDE. I now have to replace this card with an IDE one.

https://www.minuszerodegrees.net/manuals/DTC/ … ion%20Guide.pdf

That's interesting. The manual lists the DTC series numbers:

7000 Series - High Performance MFM/RLL Controllers
6000 Series - High Performance ESDI Controllers
5000 Series - Standard MFM/RLL Controllers
3000 Series - SCSI Host Adapter

Your controller isn't merely a standard RLL controller, but a "high performance" one. I wonder what that means? 8-bit vs 16-bit?
Does a high series number indicate a superior or more expensive product?

Maybe the 5000 series do not do interleave. Rest seems like marketing to me. IDE had not fully caught on by 1989 and mfm i guess was still a thing. we wouldnt see eide untill 1994 and by that time vlb became the standard.

rasz_pl wrote on 2023-08-19, 02:27:

I wouldnt call a 1989 386 system with MFM and no simm sockets high end exactly.

Back in the day in that year, IDE hard drives is starting to be used, mostly commonly in Compaq and others but most kept using the MFM, RLL or ESDI as they were little cheaper. I can remember that 80MB IDE was over 300 dollars average. (ST1102A)

Cheers,

Beautiful system. 🤗🧡

If the MFM/RLL controller is software compatible to the "AT Fixed Disk Adapter",
OS/2 1.x and Windows 3.1 might recognize it.

Those 32-Bit 4MB are nice to have for Minix, Xenix, PC-MOS/386, OS/2 and Windows/386.

All in all a solid, down-to-earth system.

That being said, it's a bit before my time.
I started with a chipset-based motherboard, too.

The MFM/RLL fixed-disk is old-school, too.
Maybe it was chosen over IDE because it was available/affordable at the time? I really don't know. 🤷‍♂️

I wonder if the board was made by a small company all by itself.
An "in-house design", so to say. Made by one cool dude with an IT/electronic degree.

The case itself isn't as remarkable. and theres a lot of surface rust inside that needs attention.
I think I want to try recapping the power supply. I haven't tested it yet and even though I inspected the caps I'm sure they're bad.

The memory board looks like it can be upgraded to 8mb. I'm not sure if there is cache onboard, It would be cool if there was at least some.

I wasn't considering upgrading the cpu with a slx2 but I have considered replacing the 50mhz crystal with a 80mhz and trying a 386dx40.

Warlord wrote on 2023-08-19, 12:49:

I can do better, I found the manual. Too bad it doesn't do IDE. I now have to replace this card with an IDE one.

You should be able to use one of the ISA Multi-IO cards from the early 486 era, serial+parallel+floppy+IDE and sometimes game.